ios - 无法更新 childAutoId 节点中的节点值以更新字典值

Question

当我向 firebase 添加新数据时，我正在开发体重跟踪应用程序，它工作正常，但是当我从该日期更新数据时，新数据正在添加现有电子邮件的唯一 ID 我想更新当前日期重量，如果我在那一天再次增加体重[黑色圆圈显示我要更新权重的位置，其余数据是实际数据正在更新的位置

这也是我的代码。

@IBAction func addButton(_ sender: UIButton) {

    let time = Date()
    let formatter = DateFormatter()
    formatter.dateFormat = "dd.MM.yyyy"
    let formatteddate = formatter.string(from: time as Date)
    if formatteddate == addDate.text!{
        self.UpdateTaskWithName(name: addWeight.text!, date: addDate.text!) { (success) in
            print("**** TASK UPDATED *******")
                DispatchQueue.main.async {
                self.navigationController?.popViewController(animated: true)

                }
            }

    }else{

        if let text = self.addWeight.text{
            if let date = self.addDate.text{

                self.saveTaskWithName(name: text, date: date, completionHandler: { (success) in
                    print("****  NEW TASK ADDED *******")
                    DispatchQueue.main.async {
                        self.navigationController?.popViewController(animated: true)
                    }
                })
            }
        }

    }

}

func saveTaskWithName(name:String,date:String, completionHandler:@escaping ((_ success:Bool)->Void)){
    let dict = ["weight": name, "date" : date] as [String : Any]
    if let userid = Auth.auth().currentUser?.uid{
        self.ref.child("WeightTracker").child(userid).childByAutoId().setValue(dict) { (error, reference) in

            if let err = error{
                print(err.localizedDescription)
            }else{
                // data save successfully
                completionHandler(true)
            }
        }
    }
}



func UpdateTaskWithName(name:String,date:String, completionHandler:@escaping ((_ success:Bool)->Void)){
    let dict = ["weight": name, "date" : date] as [String : Any]
    if let userid = Auth.auth().currentUser?.uid{
        self.ref.child("WeightTracker").child(userid).updateChildValues(dict) { (error, reference) in

            if let err = error{
                print(err.localizedDescription)
            }else{
                // data save successfully
                completionHandler(true)

             }
         }
     }
 }

Answer 1

在这个示例中，您可以执行查询 来查找您的日期与您感兴趣的日期匹配的节点，如果找到则更新。该查询将向您返回节点的 key(对于 childByAutoId 节点)，您可以使用该节点更新子 weight:

func UpdateTaskWithName(name:String, date:String, completionHandler:@escaping ((_ success:Bool)->Void)){
    if let userid = Auth.auth().currentUser?.uid {
        self.ref.child("WeightTracker")
            .child(userid)
            .queryOrdered(byChild: "date")
            .queryEqual(toValue: date)
            .observeSingleEvent(of: .value, with: { snapshot in
                self.ref.child("WeightTracker").child(userid).child(snapshot.key).child("weight").setValue(name)
            })
     }
 }

考虑到 name 您的意思是您的 date 来自 UI TextField 并考虑在内，这就是您的函数的样子。

通过将一些操作拆分为变量实例并像这样重新使用它们，还可以使该函数更易于阅读:

func UpdateTaskWithName(name:String, date:String, completionHandler:@escaping ((_ success:Bool)->Void)){
    if let userID = Auth.auth().currentUser?.uid {
        let userIDRef = self.ref.child("WeightTracker").child(userID)
        let query = userIDRef.queryOrdered(byChild: "date").queryEqual(toValue: date)
        query.observeSingleEvent(of: .value, with: { snapshot in
                let childByAutoIDNodeKey = snapshot.key
                let refToUpdate = userIDRef.child(childByAutoIDNodeKey).child("weight")
                refToUpdate.setValue(name)
                completionHandler(true)
        })
    }
}